Shrinkproofing of wool



Patented July 31, 1951 SHRINKPROOFING F WOOL Mayne R. 00c, Jr.,Washington, D. C.

No Drawing.

11 Claims.

Application February 4, 1947, Serial No. 726,449

(Granted under the act of March 3, 1883, as amended April 30, 1928; 3700. G. 757) This application is made under the act of March 3, 1883, asamended by the act of April 30, 1928, and the invention hereindescribed, if patented, may be manufactured and used by or for theGovernment of the United States of America for governmental purposeswithout the payment to me of any royalty thereon.

This invention relates to a process of shrinkproofing wool, fabricscontaining wool, and wool yarn and to the products of this process.

The surface of a wool fiber is covered with scales that overlap eachother. During the proc- 'ess of washing woolen materials, the scales ofadjacent fibers interlock and cause drawing together of the cloth. It ispossible to prevent this action by covering the surface of the fiberwith a suitable hard material, and also by penetrating underneath thescales and cementing them down; One of the undesirable features ofshrinkage control with synthetic and natural resins is the difficulty ifnot impossibility of getting complete penetration of the fiber. Caremust be taken in treating the woolen material with resins to allowenough time for the resin to work into the fibers; otherwise a spottyfinish results. In the case of oil solutions and emulsions, thepenetration is complete and instantaneous Oils are among the mostpenetrating substances known and will go into the smallest openings.This makes it possible to give an absolutely uniform finish to the clothwith no possibility of spotting merely by bringing the woolen materialmomentarily in contact with the drying oil solution or emulsion.

One object of this invention is to provide a quick and economicalprocess of shrink-proofing wool, which process also imparts otheradvantageous properties, for example, it improves the feel, reducesfelting, and increases resistance to abrasion.

In one aspect, my process comprises impregnating woolen cloth or yarnwith a dispersion of a conjugated polyolefinic, preferably triolefinic,glyceride conjugated triolefinic drying oil and then heating theimpregnated wool to a temperature sufiiciently high to cause theformation of a durable finish. The dispersion may be a 3 percentsolution of the drying oil in an oil such as gasoline, or a 3 percentdispersion or emulsion in water. The temperature and duration of heattreatment should not be such as to injure the Wool. 1

To obtain the best and most durable finish, the preferred drying oilsare the hard-drying oils, such as tung oil and oiticica oil.

synthetically produced drying oils may be used, such as dehydratedcastor oil, the separated drying components of drying oils, for examplethe elaestearic acids, the glyceride oils that have been catalyticallyisomerized to form conjugated linkages and to increase their rate ofpolymerization and. their alkali resistance, modified drying oilsobtained by esterification of fat acids with polyhydric alcohols such aspentaerythritol, mannitol,; and sorbitol, and drying oils modified byadditionof compounds having conjugated diene or polyene linkages, suchas sorbic acid.

Drying oils containing relatively high percentages of total conjugationtogether with substantial content of conjugated trienes give superiorresults.

One method of application is todip the woolen cloth or yarn into adilute, low-viscosity solution, for example 3 percent, of the selecteddrying 011 in gasoline, or'other volatilizable organic solvent.Accelerators may be added to the solution to shorten the time requiredfor the subsequent polymerization or oxidation to a durable film. Forexample cobalt or copper linoleate or naphthenate may be employed.Plasticizers may also be added. This shrink-proofing process may beapplied to clothes during a dry-cleaning process, by adding the desiredamount of drying, oil to the gasoline or other organic cleaning solvent,followed by drying, at to C., for example.

Another mode of application isto apply to the woolen fabric or yarn adilute (3 percent) suspension of the drying oil in water. Emulsifyingagents such as sodium silicate or sodium carbonate, or soap of a dryingoil are employed. An accelerator, such as potassium permanganate may beadded, in small amount, to hasten the curing step.

The amount of drying oil deposited in the wool may be varied to add anydesired weight of the oil. A film having a thickness of the order of.0001 inch or less is suitable. The treatment may be controlled to addfrom less than one percent (0.5 percent) to about 15 percent of thedrying oil by weight based upon the dry weight of the wool.

The heating operation may be carried out in two stages. In the firststage, which may be operated at a lower temperature than the second, theorganic solvent is evaporated, or the water is evaporated, where theaqueous suspension has been employed. This drying or solvent evaporationstep may be carried'out at'temperatures be low 150? C.,.for example, at100 C. or lower, at atmospheric or lower pressures, and with or with 3out the assistance of a current of air or inert gas. The curing stage,that is, the polymerization and oxidation stage is carried out at 100 to150 C., preferably at 150 C. Higher temperatures are not necessary, butmay be used provided thatthe time of exposure is very short, forexample, less than one minute. Curing in a current of air is preferred.Atmospheric, or lower or higher pressures may be employed, and an inertgas substituted for air. The hardening may increased. On successivewashings, the cloth does not unravel or felt at the edges, and the clothdoes not pucker up or decrease materially in length or breadth onwashing.

'As an example of the effectiveness of drying oils in shrink-proofing,the following percentages by weight of dried'tung oil on wool clothstrips 5 cm. by 30 cm. were given launderings in a washing machine,using 0.1 percent soap and 0.25 percent sodium carbonate solution at 55C. and the percentage of shrinkage determined.

Wt. of dried tung oil on Per cent wool cloth, shrinkage per cent As acontrol, strips of untreated wool cloth were laundered at the same time.These had an average shrinkage of about 30 percent.

Tests were made to determine the length of time necessary .for dryingthe various oils until they formed a non-washable resinous deposit onthe wool fibers. 150 (3. was found to be the best temperature at whichto dry. The wool is not embrittled at this temperature and the oils arenot decomposed. It was found advantageous to have a circulation of airin the drier. Tung oil could be dried on the cloth satisfactorily in '15minutes, whereas linseed oil needed one-half hour. The so-ealledsemi-drying and non-drying oils took considerably longer periods oftime, did not result in a durable :finish, and did not withstandlaundering.

Because of the ease of dehydrating the ricinoleic acid present, castoroil when it was treated with dehydrating agents and applied to'thecloth, dried rapidly and gave a shrink-proof finish. This was not trueof nondrying oils in general due to the absence of ricinoleic acid orother conjugated olefin structure.

A variety of finishes can be given to the wool by combinations ofsynthetic or natural resins with drying oils in a solution'or emulsionoflow viscosity and applied in-the usual manner. Alkyl resinsoralkylated melamine formaldehyde resins may be used. 1

The term dispersion employed herein includes emulsions, colloidalsuspensions, and molecular suspensions, which are solutions.

Having thus described my invention, I claim:

1. Shrink-resistant Wool being wool having an impregnated finishcomprising a heat-cured substance of the group consisting of conjugatedtriolefinic drying oils and conjugated triolefinic drying oil acids, thefinish having a thickness less than .0001 inch and constituting no morethan 4 percent by weight, based upon the dry weight of the wool.

2. Shrink-resistant wool being wool having an impregnated finishcomprising heat-cured tung oil, the finish being less than .0001 inch inthickness and constituting no more than 4 percent by weight, based uponthe dry weight of the wool.

3. Shrink-resistant wool being wool having an impregnated finishcomprising heat-cured oiticica oil, the finish being less than .0001inch in thickness and constituting no more than about 4 percent byweight, based upon the dry weight of the wool.

4. A process of reducing the shrinking and felting tendencies of woolwhich comprises impregnating wool with a dispersion in a volatilediluent of 3 percent or less of a substance of the group consisting ofconjugated triolefinic drying 'oils and conjugated triolefinic dryingoil acids,

to deposit from about 0.5 percent to about 4 percent by'weight of thecured substance, based upon the dry weight of the wool, and curing byheating the impregnated wool in a current of air at about to C. to forma durable, laundering resistant, shrink resistant, and felt resistantwool product having a finish of said heat cured substances less than.0001 inch in thickness.

5. A process of reducing the shrinking tendency of wool comprisingimpregnating wool with a dilute'dispersion of a substance of the groupconsisting of conjugated triolefinic drying oils and conjugatedtriolefinic drying oil acids, to deposit no more than about 4 percent byweight of the cured substance, based upon the dry weight of the wool,andto form a finish less than .0001 inch in thickness, and curing byheating the impregnated wool, the wool being maintained at a temperatureabove 100 C. and below the deterioration temperature of the wool.

6. The process of claim 5 in which the temperature is about 150 C.

7. A process of reducing the shrinking tendency of wool which comprisesimpregnating wool with a dispersion of about 3% or less of tung oil in avolatile diluent to deposit'no more than about 4 percent by weight ofcured tung oil, based upon the dry weight of the wool, and to form acured finish less than .0001 inch in thickness, and ouring theimpregnated wool by heating in a current of air at a temperature above100 C. and below the deterioration temperature of the wool.

-8. The process-of claim 7 in which the temperature is about 150 C.

9. A process of reducing the shrinking tendency of wool which comprisesimpregnating wool with a dispersion of about 3% or less of oiticica oilin a volatile diluent to deposit no more than about 4 percent by weightof cured oiticica oil, based upon the dry weight of the wool, and toform a cured finish less than .0001 inch in thickness, and curing theimpregnated wool by heating ina current of air at a temperature above100 C. and below the deterioration temperature of the wool. I a

5 r 6 10. The process of claim 4 in which the (115- UNITED STATESPATENTS persion is an aqueous emulsion. 7 Number Na 11. The process ofclaim 4 in which the (115- 933,598 s; $3 version is in an Organic1,973,99s Schlack et a1 Sept. 18, 1934 MAYNE JRK 6 2,022,490 Charch Nov.26, 1995 REFERENCES CITED 2,201 991 Edgar et a1 May 21, 1940 Thefollowing references are of record in the file of this patent:

4. A PROCESS OF REDUCING THE SHRINKING AND FELTING TENDENCIES OF WOOLWHICH COMPRISES IMPREGNATING WOOL WITH A DISPERSION IN A VOLATILEDILUENT OF 3 PERCENT OR LESS OF A SUBSTANCE OF THE GROUP CONSISTING OFCONJUGATED TRIOLOFINIC DRYING OILS AND CONJUGATED TRIOLEFINIC DRYING OILACIDS TO DEPOSIT FROM ABOUT 0.5 PERCENT TO ABOUT 5 PERCENT BY WEIGHT OFTHE CURED SUBSTANCE, BASED UPON THE DRY WEIGHT OF THE WOOL, AND CURINGBY HEATING THE IMPREGNATED WOOL IN A CURRENT OF AIR AT ABOUT 100* TO150* C. TO FORM A DURBLE, LAUMDERING RESITANT, SHRINK RESISTANT, ANDFELT RESISTANT WOOL PRODUCT HAVING A FINISH OF SAID HEAT CUREDSUBSTANCES LESS THAN .0001 INCH IN THICKNESS.